1. Genetic Engineering: How and why scientists manipulate DNA in living cells

2. Karyotype chart of chromosome pairs used to identify
unusual #s of chromosomes
**Down syndrome (Trisomy 21) – 3 chrom. at pair 21
Turner’s syndrome – only one X – sterile female XO
Klinefelter’s syndrome – extra X (male:XXY-sterile)
FYI Karyotype is obtained by 1) getting a sample of cells from a fetus 2) metaphase chromosomes are photographed 3) chrom. pictures are enlarged and arranged in pairs based on length and centromere location

3. Karyotype

6. Nondisjunction – causes these unusual #s of chromosomes; chromosomes fail to separate during meiosis

7. http://www. ratsteachgenetics. com/Genetics_quizzes/Lecture%207/7q1

8. Selective breeding We choose desired traits & breed plants and
animals to have these traits
*Takes decades
Examples: popcorn,
dog breeds, cows produce
3x more milk than 50 years ago, bigger peaches, apple varieties

9. Selective breeding – 2 methods
1. Hybridization – cross dissimilar individuals to bring together best traits
Ex. Crossing disease-resistant apple with high yield apple = apple tree that
produces a lot and requires
less pesticides

10. 2. Inbreeding – done to maintain traits
*because genetics are so close, often allows expression of recessive allele
Study revealed that
20,000 boxers genetically
look like 70
-deaf dalmations &
white boxers, heart disease,
hip dysplasia

11. Test cross A way of determining genotype Cross a known individual -
(homozygous recessive) with an unknown – homozygous dominant or heterozygous
If unknown is homozygous dominant, all offspring will show dominant trait
If unknown is heterozygous, some will show dominant trait, some show recessive trait
Complete Problem Solving Lab 13.1 p.339

12. Manipulating DNA Process How Cut DNA Restriction Enzymes
(like scissors)
Sort DNA
Gel Electrophoresis
Analyze DNA
DNA fingerprint

13. 1. Cut DNA: Restriction enzymes
DNA is too large to be analyzed
Highly specific restriction enzymes from bacteria cut DNA into precise pieces between certain base pairs
Ex. EcoRI can only recognize GAATTC – it cuts between the G and A
Leaves “sticky ends” – single-stranded overhangs used to bond “stick” to another DNA stand cut with the same restriction enzyme
Practice p.343
What do you remember about enzymes …they are substrate specific. Restriction enzymes are specific and only cut DNA at certain locations.

14. Restriction enzymes

15. 2. Sort DNA: Gel Electrophoresis
3. Result: DNA fingerprint
1.Insert restriction-enzyme-cut
DNA into gel
2. Add electricity.
Shorter fragments move farther
p. 346

16. 3. Analyze DNA: DNA fingerprinting
*Sample from
blood, hair, skin,
semen
*Use PCR
(polymerase
chain reaction)
to make more

17. Can you match the evidence with the suspect?
PS lab 13.3 p.353

18. Human Genome Project (1990-2003)
*Sequenced all 3 billion base pairs of human DNA and identified
all human genes.
*Used to determine
carriers for diseases
& develop gene
therapy

19. Product of Human Genome: chromosome maps

20. Genetic engineering: faster than selective breeding. Cut DNA
from one organism,
insert into another.
Recombinant
DNA: combining
DNA from different
sources

21. Transgenic organisms Contain genes from other species
Insert recombinant DNA into a new host
Use plasmid – circle of DNA in bacteria
Insert recombinant DNA into plasmid, reinsert plasmid into bacteria- bacteria clones DNA as it divides (mitosis); get lots of copies of DNA
Used to produce insulin to treat diabetes, human growth hormone, blood-clotting factors for hemophiliacs, potentially even cancer-fighting molecules (interleukin-2 and interferon)

22. Recombinant bacteria manufacture insulin

24. Cloning
Uses a single somatic cell from an adult organism to grow an entirely new genetically identical organism

25. Uses of transgenic animals
Insert spider genes into cells of lactating goats – manufacture silk along with milk = light, tough, flexible material  military uniforms, medical sutures
30% of US milk produced
by genetically modified (GM)
cows
Pigs GM to produce
high levels of lean meat

26. Transgenic plants: Golden Rice – GM to have high levels of beta-carotene – essential for health, eye sight

27. Gene therapy
Absent or faulty genes replaced by normal working genes – allows body to make proteins or enzymes needed, eliminating disorder
Used to treat SCID (severe combined immunodeficiency syndrome)
Trials for sickle-cell, cystic fibrosis, and hemophilia treatments are going on now

28. http://library. thinkquest. org/28000/media/genetherapy/l_gene

29. Future possibilities?

30. Implications? Ethical issues?
Patenting life
Genetic ownership
GINA (Genetic Information Nondiscrimination Act) passed in 2008
Protects Americans against discrimination from employers or insurance companies based on genetic information

31. http://media-2. web. britannica. com/eb-media/64/47664-004-7088EE3D